The order of the executor summary is wrong for the executor list

[SeaRise]

Bug Report

In #3937, The type of profile_streams_map is changed from std::map<String, ProfileStreamsInfo> to std::unordered_map<String, BlockInputStreams>. https://github.com/pingcap/tiflash/pull/3937/files#diff-6bc200816961f4a8ad0c24cfaf2d0975ad614e78d153fda6566c44c931908646R263

For executor list, executor_id is in the form of ${i}_${type}, so the order of map<executor_id, profile_stream> is the same as the order of executor list. And the executor summary depends on the order of the executor list.

tiflash/dbms/src/Flash/Coprocessor/DAGQueryBlock.cpp

Lines 172 to 232 in f84d7e3

	DAGQueryBlock::DAGQueryBlock(UInt32 id_, const ::google::protobuf::RepeatedPtrField<tipb::Executor> & executors)
	: id(id_)
	, root(nullptr)
	, qb_column_prefix("__QB_" + std::to_string(id_) + "_")
	{
	for (int i = executors.size() - 1; i >= 0; i--)
	{
	switch (executors[i].tp())
	{
	case tipb::ExecType::TypeTableScan:
	GET_METRIC(tiflash_coprocessor_executor_count, type_ts).Increment();
	assignOrThrowException(&source, &executors[i], SOURCE_NAME);
	/// use index as the prefix for executor name so when we sort by
	/// the executor name, it will result in the same order as it is
	/// in the dag_request, this is needed when filling execution_summary
	/// in DAGDriver
	if (executors[i].has_executor_id())
	source_name = executors[i].executor_id();
	else
	source_name = std::to_string(i) + "_tablescan";
	break;
	case tipb::ExecType::TypeSelection:
	GET_METRIC(tiflash_coprocessor_executor_count, type_sel).Increment();
	assignOrThrowException(&selection, &executors[i], SEL_NAME);
	if (executors[i].has_executor_id())
	selection_name = executors[i].executor_id();
	else
	selection_name = std::to_string(i) + "_selection";
	break;
	case tipb::ExecType::TypeStreamAgg:
	case tipb::ExecType::TypeAggregation:
	GET_METRIC(tiflash_coprocessor_executor_count, type_agg).Increment();
	assignOrThrowException(&aggregation, &executors[i], AGG_NAME);
	if (executors[i].has_executor_id())
	aggregation_name = executors[i].executor_id();
	else
	aggregation_name = std::to_string(i) + "_aggregation";
	break;
	case tipb::ExecType::TypeTopN:
	GET_METRIC(tiflash_coprocessor_executor_count, type_topn).Increment();
	assignOrThrowException(&limit_or_topn, &executors[i], TOPN_NAME);
	if (executors[i].has_executor_id())
	limit_or_topn_name = executors[i].executor_id();
	else
	limit_or_topn_name = std::to_string(i) + "_limitOrTopN";
	break;
	case tipb::ExecType::TypeLimit:
	GET_METRIC(tiflash_coprocessor_executor_count, type_limit).Increment();
	assignOrThrowException(&limit_or_topn, &executors[i], LIMIT_NAME);
	if (executors[i].has_executor_id())
	limit_or_topn_name = executors[i].executor_id();
	else
	limit_or_topn_name = std::to_string(i) + "_limitOrTopN";
	break;
	default:
	throw TiFlashException(
	"Unsupported executor in DAG request: " + executors[i].DebugString(),
	Errors::Coprocessor::Unimplemented);
	}
	}
	}

tiflash/dbms/src/Flash/Coprocessor/DAGResponseWriter.cpp

Line 25 in f84d7e3

void DAGResponseWriter::fillTiExecutionSummary(

Fortunately, executor list is currently only used in TiSpark :)